A 300 kVA, 12,000 : 4000 V, 60 Hz transformer has open-circuit test readings: 4000V, 1.1 A, 2000 W, and short-circuit test readings: 300 V, 25 A, 2800 W. 3.8 a) Which side of the transformer was...

I only need question 3.9. Question 3.8 is needed to solve 3.9.

...

Extracted text: A 300 kVA, 12,000 : 4000 V, 60 Hz transformer has open-circuit test readings: 4000V, 1.1 A, 2000 W, and short-circuit test readings: 300 V, 25 A, 2800 W. 3.8 a) Which side of the transformer was open-circuited?, short-circuited? b) What is the primary voltage, if the transformer delivers rated kVA at 0.8 pf lagging, rated voltage? c) Calculate the efficiency and voltage regulation at the above load.